Earthworking vehicles, such as track-type tractors, typically will have various implements for performing different functions. For example, the vehicle will have a dozer blade supported on a forward end of the vehicle main frame and a backhoe supported on a rearward end of the main frame. Usually, hydraulic fluid systems are employed to operate these implements under the control of the vehicle operator.
The above implements normally have different fluid flow requirements for their operation. For example, a relatively small rate of fluid flow is needed for operating the dozer blade or some other implement at the forward end of the frame, whereas a relatively large rate of fluid flow is required to run the backhoe. Because of these dual flow requirements, a problem in prior hydraulic fluid systems is that they have employed relatively complex fluid systems, including complex controls for the systems, so that different flow rates of fluid could be provided to operate the implements as needed.